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How Conifers succeed in the North

How Conifers succeed in the North. Ncumisa Mnotoza 2253897@uwc.ac.za. Conifers. All conifers are seed plants with vascular tissue that bear cones. They contain more trees than shrubs. They have monopodial growth form, that is a tall straight trunk and narrow branches.

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How Conifers succeed in the North

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  1. How Conifers succeed in the North Ncumisa Mnotoza 2253897@uwc.ac.za

  2. Conifers • All conifers are seed plants with vascular tissue that bear cones. • They contain more trees than shrubs. • They have monopodial growth form, that is a tall straight trunk and narrow branches. • They are usually found in cool or cold climatic regions. Most have evergreen leaves that are needle-like. • They are all wind pollinated. • Conifers make up 30% of the world’s forest and are a group that consists of the tallest, largest, thickest and oldest living thing.

  3. Tallest: 112.83m Coast Redwood • Largest: base trunk 31.5m volume 1486.9cm3Giant sequoia • Thickest: trunk diameter 11.42m Montezuma cypress • Oldest: 4.7 million years old

  4. SCIENTIFIC CLASSIFICATION Kingdom :Plantae Division : Pinophyta Class : Pinopsida Order : Pinales Family : Pinaceae Genus : Pinus L.

  5. Gymnosperms are plants that produce seeds not spores, the seeds are naked meaning that they are not covered by an ovary. These are non flowering plants. Usually, the seed is produced inside pine cone hence the name "conifer." In essence the name word conifer means cone bearing. Conifer are trees and shrubs that have cones and characteristically have needle-like, scale-like or awl-like leaves. Approximately 600 species are counted as conifers, and some fall under the family CONIFERACEAE. GYMNOSPERMS

  6. Gymnosperms have been distributed among four groups that have been given equal ranks in the Kingdom Plantae. Namely: • Division:Pinophyta – Conifers • Division:Ginkgophta – Ginkgo • Division:Cycadophta – Cycads • Division :Gnetophyta - Gnetum, Ephedra Coast Douglas-fir Cone

  7. Gymnosperms are not the same thing as conifers but merely a division within that group. • In very cold climatic regions conifers are the only group within the common gymnosperms that will be found

  8. Pinophyta Pinophyta it has one class, Pinopsida that includes both the living and fossil taxa. Conifers have 6 to 8 families that contains 65 to 70 genera and 600-650 species. A phylogenic diagram relates the seven most distinct families.

  9. Phlogeny of molecular data based on cladistic analysis of molecular data

  10. Coniferales There are six families within this order: • Pinaceae • Taxodiaceae • Cupressaceae • Araucariaceae • Podocarpaceae • Cephalotaxaceae

  11. Pinaceae • Leaves are linear, flat or needle-like and spirally arranged in two or more rows • Monoecious • Cones are mostly woody and spirally arranged scales • The bracts are separate from scales except at the base. The bracts are small and narrow sometimes longer than scales. The bract and ovuliferous scale are distinct • Two pollen sacs and pollen has two air bladders. Sporophyll are spirally arranged. Pollen grains are winged

  12. Juvenile (left) and adult foliage of Stone Pine (Pinus pinea). The adult shoot has dark brown scale leaves and needles. Pinophyte needle-like leaves (close- up) Picea Abies

  13. Taxodiaceace • Parts are spirally arranged • Leaves are opposite or spirally arranged, narrow, linear or awl- shaped • Monoecious • Cones have a globose scale that is spirally arranged, leathery and woody. The bract and ovuliferous scale are free when young then they fuse in the mature cone • Each ovuliferous scale has 2 to 9 ovules. Pollen sacs 2 to 9 on each microsporophyll • Pollen grains without air bladders, pollen is wingless or winged

  14. Parts are oppositely or whorled in arrangement Monoecious or dioecious Small adult leaves, scale-like arranged in opposite pairs or three Cones are small, the scales are confluent with bracts and are woody when ripe and contains numerous ovules. Ovules are erect and can be any number from 3 to 20 per scale. Cupressaceae

  15. FEATURES OF CYPERACEAE • Microsporophylls have 3 to 6 microsporangia and the pollen sacs range between 3 and 6 • Cones may overlap e.g Thunja valvate e.g Cupressus fleshy e.g Junipersus The cones are fleshy and berry-like, the seeds are bird dispersed . • Pollen grains lack air bladders and have a good drop mechanism

  16. Spiral arranged leaves that are narrow or broad with parallel veins, the buds are not scaled Dioecious or monoecious Cones have a large woody one seeded scales and no distinct bracts. Cones fall when seeds are ripe Microsporophylls consist of 5 to 20 micropsporophylls. The scale of a seed contains one ovule and is fused with a sterile bract. Ovules are solitary with microsporangia hanging from a peltate sporophyll. The male strobili is dense, cylindrical with many sporophylls Araucariacaeae (Monkey Puzzle Family)

  17. Pordocarparceae • leaves are evergreen, spirally arranged, scale-like or needle-like, linear or lanceolate, or oblanceolate • Monoeciouis or dioecious • Ovule erect or reflexed • Commonly the the ovuliferous scale is folded around the single ovule to form an added envelop, the epimatium, which is fused completely or partially to the integument or in some species it is fused to the bract scale

  18. Podocarparceae cones • Male cones have a number of microsporophylls each with 2 pollen sacs. The pollen grains have 2 or 3 air bladders. The pollen is winged • In some species the ovule are borne in cones. In others the female cone is reduced to form a fleshy receptacle with a single terminal ovule. The outer seed coat is dry or fleshy, in reduced cones or supported by a fleshy bract and stalk

  19. Cephalotaxaceae • Spirally arranged linear leaves and opposite or whorled branching • Dioecious • The ovules are borne on cones. Ovules are in pairs at the base of each opposite bracts. One ovule grows into a big olive-like seed that has an outer fleshy layer that surrounds a stony layer • The male cone have spirally arranged microsporophyll with 2 to 3 pollen sacs. The pollen bladders have no air bladders. The pollen is wingless • Pollination is a drop mechanism

  20. Reproductive Characteristics • Dioecious or monecious plants: • The microsporangiate stobili are pollen cones, that makes pollen(microgametophyes. They consist of sporophylls where the pollen sacs (microsporangia) are borne on the lower surface • All species are wind-pollinated • Sperm are not flagellated they reach the egg via a pollen tube. • Except for the Taxaceae, ovules are borne in secondarily reduced microsporangiate stobili (seed cones) with seed scales that have ovules. These are subtended by a sterile bract, together they are called a seed scale complex. They are arranged around the central axis of the ovulate cone.

  21. A GENERALIZED LIFE CYCLE OF PINES The male cone releases pollen to fertilise the ovum. The pollen is transported by wind to the female cone. When the female gamete is fertilized it is called a zygote that grows into an embryo.The embyro has integument cells that surround it and altogether can be found in the seed. When the seed is mature it drops onto the ground, and germinates. The seedlings grow into a mature plant that produces cones…and the cycle continues

  22. SUCCESS OF CONIFERS MORPHOLOGY: • A scale or a needle leaf is very small and thus has minimal exposed surface area and they are also lightweight. • This would make it impossible for trees and shrubs trap any snow on their leaves because it would not be able to support the weight of snow.The minimal surface area exposure ensures that they do lose any water that it retains. • The branches are thin, so they cannot trap much snow, or this would result in the branches breaking off the trees.

  23. Photosynthesis still occurs in extremely low temperatures due to the leaves being evergreen. These trees take advantage of the short wet and the short dry season which is characteristic of the northern climates. This mechanism allows tress to ‘save’ nutrients, because they do not have to form new leaves annualy. This is advantageous in soils with low nutrients and environments with a slow decomposition.

  24. TRACHEIDS They are long, narrow-diameter cells. Their narrowness prevents bubbles forming during spring when stems thaw. Air bubbles form as water freezes and air goes out of solution forming a gas. Due to the tracheids being narrow only small bubbles can form which end up redissolving. STOMATA They help the trees in the case of water loss and to aviod dessicatio form occuring,(as the air warms in spring the soil is still frozen and water can't move into tree freely to make up for the water loss from leave

  25. ECONOMIC IMPORTANCE • Conifers are used to make softwood timber.This wood is commonly used in temperate regions for lumber constrution making: polywoods, particleboards, and chipboards; from processed softwood, paper, plastics, tannins, turpentine. • Conifers provide food: nuts and berries

  26. REFERENCES • Chamberlain Charles Joseph, 1966. ‘Gymnosperms: Structure and Evolution’. General Publishing Company, LTD, Canada. • Dallimore W. and Jackson A. B., 1966. ‘A Handbook of Coniferaceae and Ginkgoaceae, 4th Edition. Edward Arnold LTD, London • Sporne K. R., 1965. ‘The Morphology of Gymnosperms’, Hutchinson & Co LTD, London

  27. http://en.wikipedia.org/wiki/Pinophyta

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